Abstract:In
this paper, we have investigated the thermoelectric properties
of BN-doped graphynes and compared them with respect to their pristine
counterpart using first-principles calculations. The effect of temperature
on the thermoelectric properties has also been explored. Pristine
γ-graphyne is an intrinsic band gap semiconductor and the band
gap significantly increases due to the incorporation of boron and
nitrogen atoms into the system, which simultaneously results in high electrical conductivity,
a large Seebec… Show more
“…g) Seebeck coefficient comparison of GBNS and GBNM with various samples 1‐pristine ϒ‐graphyne, 2‐ϒ graphyne with BN at the chain, 3‐ϒ graphyne with BN at the ring, and 4‐ϒ graphyne like BN sheets. [ 59 ] h) Simulation result of thermoelectric output power density with the variation of thickness of coating materials for GBNS and GBNM hybrid materials. i) Schematic diagram of Au/Gr/BN/Gr/Au device structure for tunneling current measurement, where Gr layer varies from 1 to 10 layer.…”
Pivotal to functional van der Waals stacked flexible electronic/excitonic/spintronic/thermoelectric chips is the synergy amongst constituent layers. However; the current techniques viz. sequential chemical vapor deposition, micromechanical/wet-chemical transfer are mostly limited due to diffused interfaces, and metallic remnants/bubbles at the interface. Inter-layer-coupled 2+𝜹-dimensional materials, as a new class of materials can be significantly suitable for out-of-plane carrier transport and hence prompt response in prospective devices. Here, the discovery of the use of exotic electric field ≈10 6 V cm −1 (at microwave hot-spot) and 2 thermomechanical conditions i.e. pressure ≈1 MPa, T ≈ 200 °C (during solvothermal reaction) to realize 2+𝜹-dimensional materials is reported. It is found that P z -P z chemical bonds form between the component layers, e.g., C-B and C-N in G-BN, Mo-N and Mo-B in MoS 2 -BN hybrid systems as revealed by X-ray photoelectron spectroscopy. New vibrational peaks in Raman spectra (B-C ≈1320 cm -1 for the G-BN system and Mo-B ≈365 cm -1 for the MoS 2 -BN system) are recorded. Tunable mid-gap formation, along with diodic behavior (knee voltage ≈0.7 V, breakdown voltage ≈1.8 V) in the reduced graphene oxide-reduced BN oxide (RGO-RBNO) hybrid system is also observed. Band-gap tuning in MoS 2 -BN system is observed. Simulations reveal stacking-dependent interfacial charge/potential drops, hinting at the feasibility of next-generation functional devices/sensors.
“…g) Seebeck coefficient comparison of GBNS and GBNM with various samples 1‐pristine ϒ‐graphyne, 2‐ϒ graphyne with BN at the chain, 3‐ϒ graphyne with BN at the ring, and 4‐ϒ graphyne like BN sheets. [ 59 ] h) Simulation result of thermoelectric output power density with the variation of thickness of coating materials for GBNS and GBNM hybrid materials. i) Schematic diagram of Au/Gr/BN/Gr/Au device structure for tunneling current measurement, where Gr layer varies from 1 to 10 layer.…”
Pivotal to functional van der Waals stacked flexible electronic/excitonic/spintronic/thermoelectric chips is the synergy amongst constituent layers. However; the current techniques viz. sequential chemical vapor deposition, micromechanical/wet-chemical transfer are mostly limited due to diffused interfaces, and metallic remnants/bubbles at the interface. Inter-layer-coupled 2+𝜹-dimensional materials, as a new class of materials can be significantly suitable for out-of-plane carrier transport and hence prompt response in prospective devices. Here, the discovery of the use of exotic electric field ≈10 6 V cm −1 (at microwave hot-spot) and 2 thermomechanical conditions i.e. pressure ≈1 MPa, T ≈ 200 °C (during solvothermal reaction) to realize 2+𝜹-dimensional materials is reported. It is found that P z -P z chemical bonds form between the component layers, e.g., C-B and C-N in G-BN, Mo-N and Mo-B in MoS 2 -BN hybrid systems as revealed by X-ray photoelectron spectroscopy. New vibrational peaks in Raman spectra (B-C ≈1320 cm -1 for the G-BN system and Mo-B ≈365 cm -1 for the MoS 2 -BN system) are recorded. Tunable mid-gap formation, along with diodic behavior (knee voltage ≈0.7 V, breakdown voltage ≈1.8 V) in the reduced graphene oxide-reduced BN oxide (RGO-RBNO) hybrid system is also observed. Band-gap tuning in MoS 2 -BN system is observed. Simulations reveal stacking-dependent interfacial charge/potential drops, hinting at the feasibility of next-generation functional devices/sensors.
“…2D-materials have gained significant attention during the present decade because of their novel electronic, optical, and mechanical properties compared to those of their corresponding bulk counterparts. These 2D materials are widely used in several technological applications including nanoelectronics, ,,, optoelectronics, , spintronics, , thermoelectric devices, energy storage, , hydrogen storage devices, electrodes in batteries, gas sensing, − solar cells, catalysts, etc. because of their large surface area, high mechanical and chemical stability, and enriched electrical conductivity .…”
Density functional theory methodology has been adopted to investigate the structural, electronic, and optical properties of the CdS bilayer system and compare it with the CdS monolayer. For the bilayer system, five different types of stacking modes have been considered. The binding energy calculation suggests that the AA2 stacking mode is the most energetically favorable. Both the CdS monolayer and AA2 stacked CdS bilayer possess hexagonal symmetry, but the lattice constant slightly increases in the case of the AA2 stacked CdS bilayer compared to the monolayer. The negative formation energy also concludes that the formation of both systems is thermodynamically favorable. Ab initio molecular dynamics simulation further confirms the thermodynamic stability of the AA2 stacked CdS bilayer system. The band gap increases in the bilayer system compared to the monolayer as well as the bulk form, and both systems show direct band gap semiconducting character. Similar to the monolayer, the CdS bilayer system is also a promising candidate for visible light-driven photocatalysis. The optical band gap calculation for CdS sheets shows its possible usage as a light harvester. Moreover, the optical band gap, as well as absorption spectra, shows a redshift for the AA2 stacked CdS bilayer as compared to the CdS monolayer. A redshift in the optical band gap, as well as the absorption spectra, is observed for the AA2 stacked CdS bilayer with respect to the monolayer. The CdS monolayer and bilayer systems exhibit outstanding optical responses that confirm their potential applications in optoelectronics.
“…Many researchers have explored the structural and optoelectronic properties of BN-doped graphynes with different configurations. 31,32,43,44 Inspired by the above studies, we selected graphyne as the parent for BN substitution and constructed five BN pair-substituted graphyne systems. We then explored the effect of alkali metal (Li, Na, and K) doping on the electronic and NLO responses of hybrid systems.…”
Section: Introductionmentioning
confidence: 99%
“…Over the years, many potential applications of BN pair-doped graphyne derivatives have been systematically studied. For instance, BN-codoped GDYs can be used as promising electrocatalysts , and chemical nanosensors, and BN-doped graphynes are excellent candidates for UV light protection and thermoelectric applications . Besides, BN pair doping proved to be an efficient strategy to enhance the NLO responses of compounds (such as graphene, biphenylene, heterofullerene, and carbon nanotube). − It is also found that the type and size of the BN domain have a significant effect on the β 0 value of the hybrid CNT system .…”
Section: Introductionmentioning
confidence: 99%
“…In this study, the geometric, electronic, and nonlinear optical properties of alkali-doped, BN-pair-substituted graphynes were investigated by employing density functional theory (DFT) calculations. Many researchers have explored the structural and optoelectronic properties of BN-doped graphynes with different configurations. ,,, Inspired by the above studies, we selected graphyne as the parent for BN substitution and constructed five BN pair-substituted graphyne systems. We then explored the effect of alkali metal (Li, Na, and K) doping on the electronic and NLO responses of hybrid systems.…”
The electronic and nonlinear optical
(NLO) properties of BN-substituted
graphynes and the corresponding alkali-doped hybrid systems have been
determined using density functional theory. When the carbon atoms
in the graphyne are replaced by BN pairs, the highest occupied molecular
orbital–lowest unoccupied molecular orbital (HOMO–LUMO)
gap (E
gap) increases to some extent, and
the static first hyperpolarizabilities (β0) of the
novel systems hardly increase. However, when an alkali atom is introduced
on the surface of BN-substituted graphyne, the doping effect can effectively
modulate the electronic and NLO properties. Doping the alkali atom
can significantly narrow the wide E
gap of BN-substituted graphynes in the range of 1.03–2.03 eV.
Furthermore, the doping effect brings considerable β0 values to these alkali-doped systems, which are 52–3609 au
for Li-doped systems and 3258–211 053 au for Na/K-doped
ones. The result reveals that the β0 values of alkali-doped
complexes are influenced by the atomic number of alkali metals and
the proportion of BN pairs. The nature of the excellent NLO responses
of alkali-doped complexes can be understood by the low excitation
energy of the crucial excited state and the analysis of the first
hyperpolarizability density. Besides, these alkali-doped complexes
have a deep-ultraviolet working region. Therefore, the combined effect
of alkali metal doping and BN substitution can be an excellent strategy
to design novel high-performance NLO materials based on graphyne.
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